A Russian EVA was conducted outside of the International Space Station (ISS) with two Russian cosmonauts deploying several nanosatellites, collecting research samples and performing structural maintenance. Expedition 52 Commander Fyodor Yurchikhin and Flight Engineer Sergey Ryazanskiy exited the station’s Pirs airlock at 14:36 UTC and ended it after seven hours and 34 minutes.
Named EVA-43 – or RS-43 – in the Russian spacewalk listings, both spacewalkers were wearing Russian Orlan spacesuits bearing blue stripes, although Although Yurchikhin’s suit was Orlan MKS number 4, with number 6 for Ryazanskiy.
The highly experienced Yurchikhin was designated extravehicular crew member 1 (EV1) for this spacewalk, which was the ninth of his career. Ryazanskiy (EV-2) is no stranger to heading outside of the orbital outpost and was embarking on his fourth spacewalk.
This was the first Russian EVA of the year. The previous EVA took place in February 2016.
The first order of the day was for Ryazanskiy to head into the manual deployment of five nanosatellites from a ladder outside the airlock, following set up tasks including the hosting of a Go-Pro camera.
The satellites, each of which has a mass of about 11 pounds, have a variety of purposes.
One of the satellites, with casings made using 3-D printing technology, will test the effect of the low-Earth-orbit environment on the composition of 3-D printed materials. Another satellite contains recorded greetings to the people of Earth in 11 languages.
A third satellite commemorates the 60th anniversary of the Sputnik 1 launch and the 160th anniversary of the birth of Russian scientist Konstantin Tsiolkovsky.
The spacewalkers also – as is commonplace for a Russian EVA – collected residue samples from various locations outside the Russian segment of the station and installed handrails and struts to facilitate future excursions.
The spacewalk – was scheduled to last six hours, but was extended as they fell behind the timeline – was the 202nd in support of space station assembly and maintenance and the seventh spacewalk this year.
The EVA came just a day after the arrival of the CRS-12 Dragon spacecraft, which had to fit into the schedule of the Russian EVA. With Dragon’s launch vehicle – Falcon 9 – holding a secondary priority to the upcoming Atlas V launch with TDRS-M, Dragon also had to conduct a single shot launch attempt, or face a several day delay.
The relevance to the Russian EVA was due to the satellite deployment element of the spacewalk, which held a conjunction threat had Dragon not been berthed to the Station. In the end, Dragon launched at the first attempt and berthed with the Station on Wednesday morning without issue.
Incidentally, there was an additional item of interest for Dragon’s ability to arrive within this short window of opportunity, relating to the communication systems on the ISS.
“Remote Power Controller Module (RPCM) P12B_B Trip – Remote Power Controller (RPC) 10 of RPCM P12B_B tripped,” noted L2 ISS Status information. “This RPC powers the S-Band transponder for String 2. There were no impacts to voice or telemetry as S-Band String 1 was and continues to be prime. String 2 was in hot backup for ACS/UHF Audio Interface (AUAI) troubleshooting.
“The trip signature indicates a Field Effect Transistor (FET) Hybrid failure which would be the first occurrence for this RPC. Multiple closure attempts of RPC 10 were performed with no success.
“Two fully functional strings of ISS S-band are required per the SpaceX Dragon Launch Commit Criteria (LCC) Flight Rule. A Failure Investigation Team (FIT) met this morning to discuss and recommend a forward plan. This is an external RPCM that can be Removed and Replaced (R&R) by the Special Purpose Dexterous Manipulator (SPDM).”
With the Station using both S-Band and Ku-Band for communications, the ISS teams worked to checkout both systems in relation to both Dragon’s arrival and the Russian EVA.
“Ku Band Contingency Command and Telemetry (CCT) Checkout – In response to the loss of S-Band redundancy due to the loss of power to the S-Band-2 transponder, ground teams completed a checkout of the Ku-Band CCT command and voice capability,” added the notes.
“During the test all control centers, including Sp-X Mission Control, successfully sent test commands to ISS via Ku-Band. Additionally, Ku-Band voice between ISS and MCC-Moscow was verified in the event this is needed during the upcoming Russian Extra-Vehicular Activity (EVA).”
While both the Dragon and EVA operations were cleared to proceed with the aforementioned steps, the ISS teams will go ahead and restore redundancy by putting the Canadian robot Dextre (SPDM) to work, potentially before, during, or after the Russian EVA, as originally planned.
While it would have been a unique event for the robot to be busy conducting a task on the outside of the Station while two human colleges were also at work, the work sites are far apart and would not provide any distractions.
“The trip signature indicates a Field Effect Transistor (FET) Hybrid failure. This is an external RPCM that can be Removed and Replaced (R&R) by the Special Purpose Dexterous Manipulator (SPDM). Planning is underway to perform this R&R NET August 18th.”
However, as somewhat expected, ISS managers opted to delay Dextre’s task to next week.
“An R&R will not be attempted this week. However, teams are working to schedule the RPCM R&R during the favorable beta range that ends on 8/30/17.”
(Images via NASA and Roscosmos).